Line of Sight

Characters can only attack or take action against targets that they can see, at least partially. If it’s not possible to trace a line to some part of a target – perhaps because it’s completely blocked by cover or terrain – then they can’t be attacked.

Line of Sight doesn’t imply visibility alone, but also a clear path for your attack – line of effect. Even if you can somehow see an area that’s behind a solid wall (using a remote drone, for example), you can’t attack targets within.

Arcing weapons are designed to lob projectiles over obstacles. They can be used to attack targets without Line of Sight, although they are still affected by Cover and the attack must be physically possible – an arcing weapon still can’t fire through 50 feet of metal bulkhead.

Powerful seeking weapons completely ignore Cover and Line of Sight, as long as it is physically possible to reach the target. Seeking weapons are usually self-guided, self-propelled, and able to navigate complex environments.